Unlock instant, AI-driven research and patent intelligence for your innovation.

Method and system for transmitting a signal via a non linear transmission unit

Inactive Publication Date: 2003-03-27
NOKIA CORP
View PDF7 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0009] Starting form that prior art it is the object of the invention to improve the dynamic range of a system and method for transmitting a signal via a non-linear transmission unit.
[0013] Thus the linearity of the system and in particular of the transmission unit is improved and distortions of the signal output by the system are reduced. Instead of expensive transmission units having an improved linearity low cost transmission units can be used.
[0015] Advantageously, the system comprises a second amplifier for amplifying the control signal after being transmitted via said main transmission device or via said other transmission unit but before being input to the first amplifier. Said second amplifier compensates losses in said other transmission unit in the way that the control signal applied to the controlled first amplifier is the same as input to said variable attenuator. In that way exact reversion of the attenuation by said controlled first amplifier is ensured.
[0016] According to another embodiment the system advantageously comprises another transmission unit for transmitting the control signal to the first amplifier. No high linearity characteristics are required for said other transmission unit with the result that low cost components, in particular low cost digital laser diodes or cheap light emitting diodes LED may be used. The system is based on the idea that variations in the input / output power occur over a slower time scale for most cellular protocols as for a wideband code division multiple access (W-CDMA) or for a global system for mobile communications (GSM) transmissions. Therefore, no phase adjustment device are required.
[0021] The object is further solved by a restoration unit to be used in a system as mentioned above and comprising the amplifier. Said restoration unit advantageously enables a proper recovering of the signal from the transmitted main signal.

Problems solved by technology

However, fiber-optic links are non-linear transmission units, in particular due to the non-linear behaviour of the laser diode.
However, both ways are very expensive.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method and system for transmitting a signal via a non linear transmission unit
  • Method and system for transmitting a signal via a non linear transmission unit
  • Method and system for transmitting a signal via a non linear transmission unit

Examples

Experimental program
Comparison scheme
Effect test

first embodiment

[0033] FIG. 1 shows the system according to the invention. The system comprises a preparation unit 100, transmission units 200 and a restoration unit 300.

[0034] The preparation unit 100 comprises a power splitter 110 for dividing a signal, hereinafter referred to as input signal, into a main signal and an auxiliary signal, wherein the ratio of the power of the main signal and the power of the auxiliary signal is e.g. 1:10. The auxiliary signal is communicated to a power variation detector 120 for detecting power variations in said auxiliary signal and for generating a control signal representing said power variations. For achieving this the power variation detector 120 comprises a power detector 124 filtering a power signal out of said auxiliary signal and outputting said power signal to a comparator 126 also being comprised within said power variation detector 120. Said comparator 126 compares the power of said power signal with a predetermined reference power value P.sub.ref repre...

second embodiment

[0047] FIG. 2 shows the transmission unit of the system according to the present invention shown in FIG. 1. According to FIG. 2 both signals the main signal and the control signal, respectively, are transmitted via the same optical fibre 260, using WDM technique.

[0048] In order to achieve this in its second embodiment 200' the transmission unit is embodied as fibre-optic link comprising a laser diode 250 for converting the main signal into a first optical signal and comprising a light emitting diode 250' for converting the control signal into a second optical signal. Said first and second optical signals are both communicated to a multiplexer 210 for generating a multiplex signal by multiplexing said two optical signals. The multiplex signal is an optical signal, too, being output from said multiplexer and transmitted via an optical fibre 260 to a demultiplexer 220. The demultiplexer 220 serves for separating said first and said second optical signal from said transmitted multiplex ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention relates to a system and method for transmitting a signal via a non-linear transmission unit, wherein the system aims to reduce distortion in the signal after transmission caused by intermodulation products. For achieving a decrease of intermodulation products in the output signal the system comprises a power splitter 110 for dividing the signal into a main signal and an auxiliary signal. The system further includes a power variation detector 120 for detecting power variations in said auxiliary signal and for generating a control signal representing said power variations. The system further includes a variable attenuator 130 for attenuating the power of said main signal in response to said control signal such that the said power of the main signal being input to said non-linear transmission line 200a is kept constant if the power of the input signal exceeds a predetermined reference power value Pref. After transmission the signal is recovered by amplifying the main signal by a first variable gain amplifier 310 in response to said control signal.

Description

[0001] The invention relates to a method and system comprising a preparation unit and a restoration unit for transmitting a signal via a non-linear transmission unit, in particular a fiber-optical link.[0002] Such systems are for example known from Satellite or telecommunications application. These applications usually require a high dynamic range, preferably in combination with a band width of several MHz, for the transmission units because the power of typical input signals can vary in a dynamic range of e.g. 100 dB.[0003] A traditional approach for fulfilling these requirements is to use fiber-optical links as shown in FIG. 8. Such fiber optical-links have the advantages of low loss, high bandwidth and low-weight. According to FIG. 8 they comprise a laser diode 850 for receiving a signal and transforming said signal into a modulated light signal. The fiber-optical link further comprises a fiber 860 for transmitting said light signal to a photo diode 870 which restores the signal ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): H04B10/155
CPCH04B10/504H04B10/564H04B10/58H04B10/503
Inventor BOGOD, LEONID
Owner NOKIA CORP